1. Field of the Invention
The present invention relates to unit-shaped masonry blocks, and more specifically to dry-stackable masonry unit configurations and methods of erecting dry-stackable masonry unit structures.
2. Description of the Prior Art
Masonry construction blocks and methods for constructing various kinds of brick or block walls are well known in the art. Because of the difficulty and high cost of constructing walls of quarried stone or block, cast cementitious blocks long ago replaced quarried stone as a preferred material in many applications.
Cast blocks typically have a uniform size and shape, include at least one cavity, and frequently permit physical interlocking, either vertically or horizontally, with integrally formed or independent connection means. Such interlocking designs facilitate rapid assembly and proper alignment during fabrication. They also permit assembly without mortar, so that some designs of cast blocks may be employed for temporary walls that can be easily disassembled.
Walls constructed of cast blocks may rely exclusively on the mass of the blocks to maintain alignment and stability. However, mortarless cementitious cast block walls intended for permanent use usually require additional stability. Accordingly, many designs permit mortar or reinforced concrete to be poured or injected into and to fill gaps and aligned vertical and horizontal openings in the blocks.
However, along with their advantages, the known cast blocks also have many disadvantages, including: difficulty in converting the wall units into end or corner units; lateral instability; vulnerability of exposed mortar to chemical or environmental degradation; expansion and contraction of mortar, causing cracking and separation of blocks; difficulty in constructing curved configurations; and vulnerability of broad flat surfaces to defacement and graffiti.